Resveratrol inhibits the virulence of Vibrio harveyi by reducing the activity of Vibrio harveyi hemolysin

Vibrio harveyi is a kind of pathogenic bacteria that occurs widely in the ocean and exhibits multiple drug resistance. V. harveyi hemolysin (VHH) is the essential virulence factor of V. harveyi, and its main function is to promote the entry and spread of V. harveyi by lysing the cell membrane, which plays a critical role in the pathogen infection of the host. In this study, we used VHH as the target protein of novel virulence factor inhibitors and found that resveratrol (RSV) significantly inhibited its hemolytic activity. Furthermore, we investigated the mechanism of action of RSV and evaluated its therapeutic effect in V. harveyi-infected Takifugu rubripes. Remarkably, RSV downregulated the transcription of the vhh gene within a concentration range that did not inhibit bacterial growth. In addition, RSV antagonized its hemolytic activity by directly binding to the active center of VHH. RSV could effectively inhibit the damage caused by VHH and V. harveyi both in vitro and in vivo. These results suggest that RSV is a promising agent for the treatment of V. harveyi infection.